import/export route targets from E-BGP ?

Unanswered Question
Oct 6th, 2007

hi all,

a newbie question again,

can i import/export rte target in a vrf from/to ebgp session,

in all my readings i only see samples from import/export with iBGP peering

thanks for answer

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william.caban Sun, 10/07/2007 - 14:34

I'm not sure what are you trying to accomplish but if you want to transit MPLS information between providers you have to use either:


1) BGP with the send label applied to the neighbor

2) Have BGP vpnv4 peering with your neighbor and have the extended community information being exchanged.


These are the two common ways of exchanging MPLS information between carriers.


Hope this helps.


-W

william.caban Sun, 10/07/2007 - 14:46

As clarification to the previous post some examples:


1) Send label: (from provider1)

!

rotuer bgp 100

...

neighbor 1.1.1.1 remote-as 200

neighbor 1.1.1.1 description eBGP Provider2

...

address-family ipv4

neighbor 1.1.1.1 activate

neighbor 1.1.1.1 send-label

...

!


2) Having a VPNv4 Peering between RRs:

From provider1 RR to provider2 RR:

!

router bgp 100

...

neighbor 2.2.2.2 remote-as 200

neighbor 2.2.2.2 description eBGP Provider2

...

address-famility vpnv4

neighbor 2.2.2.2 activate

neighbor 2.2.2.2 send-community extended

neighbor 2.2.2.2 next-hop-unchanged

...

!


Hope this helps,


-W

a.diot Mon, 10/08/2007 - 09:13

thanks for answer can i do this :


int vrf test

rd 100:1

import rt 100:1

export rt 100:1


router bgp 100

...

neighbor 2.2.2.2 remote-as 200

neighbor 2.2.2.2 description eBGP Provider2

...

address-famility vpnv4

neighbor 2.2.2.2 activate

neighbor 2.2.2.2 send-community extended

neighbor 2.2.2.2 next-hop-unchanged

...

as u can see no ibgp peering


Thanks

swaroop.potdar Mon, 10/08/2007 - 09:31

Yes you can do it this way as well, without the MP-EBGP peering between the both AS's RR's. (You have missed the multi-hop neighbor statement)


This will achieve the RT exchange between the PE's, so next you will have to import that RT on the other side.


Once you have the RT with the routes exchanged you will have VPN labels as well populated for the routes on the remote side.


Now you will have to implement a method to assign an IGP label on top of the VPN label (this label should be for the PE's loopback of AS 100 who advertised this route to AS 200)


In your case, you can use the send-label command at the ASBR's for the IGP route of the PE;s in their AS' with a label. For this you can redistribute IGP into BGP and again BGP into IGP (with a route-map matching only PE's loopback in their AS and the remote AS).


So you will effectively have 2 labels to switch traffic between the AS's (IGP and the VPN label).


HTH-Cheers,

Swaroop

etienne.basset Sun, 10/07/2007 - 22:58

hello,


yes you can, as RT is an extended attribute, passed in BGP update (if send commuty ext)

To exchange vpnv4 routes between providers you must have the following (very simplified) :

- an e-BGP vpnv4 session between AS

- a label assigned for next-hop between AS;

you should read 'mpls & vpn architecture vol2', which is a very good source for this kind of setup


regards

Etienne

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